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Streptococcal pyrogenic exotoxin B enhances tissue damage initiated by other Streptococcus pyogenes products

M Saouda1, W Wu, P Conran

  • 1Department of Microbiology and Immunology, Medical College of Ohio, Toledo, USA. msaouda@mco.edu

The Journal of Infectious Diseases
|August 23, 2001
PubMed

Insights

Streptococcus pyogenes strains positive for streptococcal pyrogenic exotoxin B (SpeB) cause severe tissue damage in mice. SpeB contributes to necrosis, but its presence alone does not cause infection.

Area of Science:

  • Microbiology
  • Pathology
  • Immunology

Background:

  • Streptococcus pyogenes is a significant human pathogen.
  • Streptococcal pyrogenic exotoxin B (SpeB) is a major virulence factor.
  • Understanding SpeB's role in pathogenesis is crucial for developing targeted therapies.

Purpose of the Study:

  • To compare the pathological effects and infection patterns of SpeB-positive and SpeB-negative Streptococcus pyogenes variants.
  • To elucidate the specific contribution of SpeB to tissue damage and necrosis.

Main Methods:

  • Utilized an M1 isolate of Streptococcus pyogenes with isogenic SpeB-positive and SpeB-negative variants.
  • Employed a mouse skin air sac model to assess pathology and infection.
  • Administered purified SpeB alone and in combination with bacterial variants.

Main Results:

  • SpeB-positive strains induced severe, extensive local tissue damage compared to SpeB-negative variants.
  • Histological examination revealed distinct differences in necrosis and host inflammatory responses.
  • Purified SpeB alone did not cause significant tissue damage, but enhanced necrosis when coinjected with bacterial strains.

Conclusions:

  • SpeB is a key contributor to the severe pathology and tissue necrosis caused by Streptococcus pyogenes.
  • The context of bacterial presence is necessary for SpeB to exert its full pathogenic effect.
  • SpeB's virulence is dependent on the specific bacterial strain and its recovery state.

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